Apparatus for manufacturing lock nuts



March 15, 1949. J. w. Ngs-'F APPARATUS FOR MANUFACTURING LOCK NUTS 11 Sheets-sheet 1 l] 1 'flllllv.. im M w Sm. R m n EW w n l A W f ma d 1 am .knwsfdwlllduvlhnl \.A. um .d if@ E lls N\\ b E= m--. MMwmHH ni WHM. I o n R March l5, 1949. J. w. NEFF APPARATUS FOR MANUFACTURING LOCK NUTS 11 sheets-sheet 2 Filed Oct. 9, 1945 mmm NNN March 15, 1949. w, NEFF APPARATUS FOR MANUFACTURING LOCK NUTS 11 Sheets-Sheet 5 Filed OOC. 9, 1945 R N x NNN INVENTOR JOHN 14./ A/.EFF

BY 'LMWQQJM ATTORNEYS mwN,

March l5, 1949. J. w NEFF APPARATUS FOR MANUFACTURING Locx NUTS Filed oct. 9, 1945 11 Sheets-Sheet 4 March l5, 1949. J. w, NEFF APPARATusvFoR MANUFACTURING Locx NUTS 11 Sheets-Sheet 5 L Filed Oct, 9, 1945 INVENTOR do/f/v l/V. /VEFF @Mut ATTORNEYS March 15, 1949. J. w. NEFF A APPARATUS FOR MANUFACTURING LOCKv NUTS 11 Sheets-Sheet 6 Filed Oct. 9, 1945 F La N5 mw .Mm w n IN ,A H` @Y March 15, 1949. J. w. NEFF 2,454,411

APPARATUS Fon MANUFACTURING Loox Nurs Filed oct. 9, 1945 11 sheds-sheet 'I lNvEN-roR JOHN PY.' /VEFF Z5 ATTORNEYS March 15, 1949. J, w, NEFF 2,464,411

APPARATUS FOR MANUFACTURING LOCK NUTS Filed Oct. 9, 1945 11 Sheets-Sheet 8 INVENTOR QOH/V "f /V'FF ATTORN EYS ,March 15, 1949. J. w. NEFF APPARATUS FOR MANUFACTURING LOCK NUTS .l1 ISheets-Sheet 9 Filed OCf..v 9. A1945 INVENTOR JO/MlV IV. /VEFF BY bwk M ATTORNEYS (y. am

March 15, 1949. J w NEFF 2,464,411

APPARATUS FOR MANUFACTURING LOCK NUTS Filed Oct. 9, 1945 1l Sheets-Sheet 10 ATTORNEYS March 15, 1949. J. WQNEFF APPARATUS FOR MANUFACTURING Loox NUTs 11 She'etS-Sheei'. l1

Filed Oct. 9, 1945 NNN IIIIHHHII! I WM R 5 my mw ww MN .mw H A O f J .Y .B 51 1 r A. V L 1l EN L n u Q Ku/ Patented Mar. V, 1.1949

` APPARATUS Fon MANUFACTURING Loox NUTS

-John W. Neff, Easton, Pa., assignor to -Stover Lock Nut & Machinery Delaware l Corporation, a corporation of` application october 9, 1945, 'serial No. 621,272

'TIhis invetionrelates' to lock n'uts and has for 4 its-.object certain improvements in the'apparatus Nutsordmarny are made with a pitch diameterv suicientlyfgreater than the pitch diameter of a matingbolt' so'fthat'the nut may be'screwed freely 9 claims. (ci. 10-72) ontothlebolt.` y This so-called fit tolerance may f vay.considerablydepending upon the size of the nutrandV the'neness-of fit desired. In `any even, however, it s-sflcie'nt yso"thatfuntil the n'ut on the bolt comes into engagement with the work to bel-held, .the threads vofthe-nut do not `exert any substantial pressure on.' either the .upper or the.

lowenside fof the bolt threads;l and. in consequence there is only slight friction andfresistance to turning. When the nut. becomes tightened against rthe'work, the upper sides ofthe threads o nzthe nut contact thelower` sides of the threads onthe boltwith apressuredetermined by the force with whichthezfnut isftightened, and the friction'resu-lting fromthe--pressure between the' inter-engaging sides of the threads serves to hold the nut vin its tightened position.

The-objection to. this kindof nut is that-it is easilyK loosened, because whenever` the pressure between the lower end of the nut and the Work isA relieved as a result of vibration, wear, orother cause, the pressure betweenthe inter-engaging sidesfof `the' threads is also relieved so :that there is nolonger 'suiilcient friction to prevent the nut from being slowly .backedcffthe bolt by vibration, shock, or the like.

Many different expedients have ,been proposed, and some have comeinto general use, to prevent accidental loosening of tightened nuts. The wellknown split lockwasher, the use of a separate lock nutand the use of `cotter pins through cotter ways formed inthe nut'and through a hole in the bolt, are probably kthe most familiar of these expedlents'- Another proposal is to insert elastic material in a groove specially provided around the threadedv hole of a nut to provide a locking effect. The eiective` yuse `of such a nut is limited to the life ofthe elastic material while continued in use with the work to which it is rst applied or the nut'is` Igreatlylimitedin thenumber of times it can be re-used because of damage to and loss of elasticity ofthe elastic'materiaL Other expedients have` involvedv cutting specially shaped and finely-made,t-hreadsfon` both-"nut and bolt, and the provision of special lock sections formed integrally with yorjattached Ato the nut, Proposals also have beenimade to' deform the nut as a whole, r`or to"providegspecially.'formed sections of the nut whichy may be` deformed to lock with the no commercialsuccess.

formed too little, it is worthless..` If it is deformed bolt.' Such sections often are slotted in various ways with the idea of enhancing the locking action of the deformed section.r These various prior expedients are subject to the disadvantage that a I separate looking piece is required, or tothe dis-' v advantage of being ineffective or only moderately effective, and difllcult and expensive to manufacture accurately and in quantity. For example,r proposals 'to distort the nut over its entire length have been unsuccessful, because nuts so distorted i to an effective degree "cannot be started on the bolt except with great diiculty.v Proposals to deform specially provided sections of the bolt have been unsuccessful because the deformed sections,

which commonly are slotted in some manner, dof

not provide -a satisfactory lock and are expensive to manufacture. n

Anotherlock nut proposed is one with opposite sides of a blank nut forced toward one another toy provide an oval or elliptical opening at the top while maintaining the lower part of the hole of the nut cylindrical or circular.' Although such a.

lock nut was proposed many years ago in British Patent I1003 of 1880,fso far `as is known it has had If the lock nut is detoo much, it isnot satisfactoryrbecause use of the lock nut damages the threads of the nut as well as of the bolt or-mating screw,and the desired non-slipping gripping action is not obtained.

If the yinsuiiciently deformed lock nut is given additional deformation, there is however no wayof .telling whether the deformation is too much or too little, except by "actual use. Actual use is out of the question when the lock nuts are made by the thousands and' shipped to remote parts for unfailing use. y e

Investigation confirms my discovery that lock nuts of the proper type and amount of deformation may be consistently reproduced or duplicated and that the deformation is suilcient to assure adequate gripping or locking action between the lock nuts and their mating bolts or screws.

The lock nut preferably comprises a nut blank having a threaded opening, opposite sides of the main body of the blankbeing compressed at the top portion thereof to a depth of 1/4 to 1/2 the,

nominal diameter of the mating screw beyond the elastic limit of the blank to provide a permanent distortion in the blank and to cause the top of the open'ing to assume a generally elliptical shape with the sides of the opening on the minor axis pushed toward one another and with the sides of the opening on the major axis pushed away from one another while the bottom of the opening remains substantially circular with a diameter greater than the minor axis and less than the major axis. The width of the top of the opening along the minor axis is reduced by the distortion by an amount equal to the fit tolerance plus 0.001 to 0.010 inch.

In a presently preferred practice, the width of the top of the opening along the minor axis is reduced by the distortion by an amount to produce a fraction locking torque of 115 Dl-4 to 820 D on a mating screw within the dimension tolerances of its class of t in which D equals the-nominal diameter of the mating screw and v the result obtained is pound inches of torque.

In accordance with the invention, the apparatus comprises a mandrel adapted to be inserted in the threaded hole of a nut blank, the mandrel being provided with a stop portion of predetermined size, forcing means for moving opposite sides of the nut toward one another until threads in the hole of the nut engage the stop portion of the mandrel to distort the nut a predetermined amount, and a knurling device associated with the mandrel and the forcing means for knurling the top of thefnut.

The depth ofsqueeze of the upper portion of the main body of the blank is highly important. A decrease in the depth of squeeze results in less sensitivity (variation of friction torque in relation to change in bolt diameter) to bolt diameter and less life (re-use factor). An increase in the depth of squeeze results in greater sensitlvity to bolt diameter and greater life. The object is to select a depth of squeeze adapted to yield the least sensitivity with the greatest life. If the depth of squeeze is less than A of the bolt diameter, the life of the lock nut is less than its practical limit. If the depth of squeeze is more than 1/2 of the bolt diameter, the sensitivity of the lock nut is beyond the practical limit'. For these reasons, opposite sides of the main body of the blank are compressed only at the top portion thereof to a depth of A to 1/2. preferably about the nominal'4 diameter of the mating screw or bolt. This is particularly true of nuts ranging, for example, from #8 machine screw to 1" in size.

Lock nuts of the character described may be readily applied to a bolt or mating screw. They may be screwed on part way by hand'since the lower part of the nut is substantially undistorted. At this point, the inwardly slanting opposite sides of the threaded opening in the nut come into contact with the bolt threads and as the nut is screwed on further, the bolt threads force the compressed sides of the nut apart against the spring action of the distorted nut.

These and other advantages of the invention will be better understood by referring to the ac companying drawing, taken in conjunction with the following description, in which- Fig. 1 is a side elevation of an apparatus illustrative of a practice of the invention, for the -most part showing its inner mechanism and not its outer casing or covering;

Fig. 2 is a partial plan view of the loading end of the mechanism;

Fig. 3 is a. sectional elevational view showing the endless conveyor and part of the driving mechanism, the view being taken on a vertical plane along the path of movement of the nuts as shown in Fig. 7;

Fig. 4 is a partial plan view of the endless conveyor;

Fig. 5 is an exploded view of a unit of the end f rolls;

less conveyor showing a sprocket chain link, a mandrel support and a` mandrel with a nut mounted thereon;

Fig. 6 is a fragmentary side view of a small section of the endless conveyor;

Fig. 7 is asectional plan view on the line 1-1 of Fig. 1',` snowing the 4endless conveyor, the squeeze rolls, the driving mechanism for the endless conveyor, the adjustingv mechanism for moving the endless conveyor laterally and a portion of the driving mechanism for the knurling device;

Fig. 8 is a sectional view on the line 8-8 of Fig. 1, showing the mounting of the squeeze rolls,

the mechanism for driving the same and a portion of the adjusting mechanism for moving lone of the squeeze rolls laterally;

Fig. 9 is a. fragmentary sectional view on the line 9 9 of Fig. 8, showing the adjusting meclil-v anism 'for moving the Aendless conveyor and its associated parts laterally, the squeeze rolls Iin t phantom and part of the vadjusting mechanism f for moving one of the squeeze rolls laterally;

Fig. 10 is an enlarged sectional viewof the mandrel support, showing a generally cylindrical mandrel and a nut mounted thereon, before it is y Fig. 13 is a planv view 'of a lock nut illustrative .Y y

of the invention;

Fig. 14 is a side elevation; I

Fig. 15 is a perspective view partly in section:

Fig. 16 is a side elevation partly in section, showing the lock nutand a bolt in applied form;

Fig. 1'7 is a view similar to Fig. 9, but showing the relative relation of the parts when deforming a smaller nut; y

Fig. 18 is a section on the line |8--I8 of Fig. 17, showing the aligning. mechanism for presenting a pair of opposite sides ofthe nut to the squeeze endless conveyor support and its related parts,l

the endless conveyor itself being omitted except for its chain sprockets, which are shown in phantom:4

' Fig. 22 is an enlarged elevational view of the knurling device shown in Figs. 1 and 3;

Fig. 23 is an end view of the same knurling device;

Fig. 24 is a section on the line 24-24 of Fig.

Fig. 25 is a plan view confined -to the tension control mechanism of the knurling device;

Fig., 26 is a sectional view on the linef26-26 of Fig. 23; g

Fig. `27 is an enlarged eievationalviewof the adjusting mechanism for moving one of the squeeze rolls laterally, as shown in Figs. 1, 7, 8,

9, 17 and ,19, and showing more particularly the showing the amount of lateral movement of the squeeze roll; and u ing block l13 by means of a plurality"of'bolts. Inv

Fig. y28 is a frontview of the yindicator and its v associated mechanism..

Referring nrst to Fig. 1, the nut deforming and knurling apparatus, comprises a pair of up-y right spaced pedestals`30 Vand 3|' maintained' in spacedrelationship at their bottom by means of a plurality of channels 32, 33. The pedestals in turn support a loading table 34,'a casing or cover 35, most of which is shown broken away, an endless conveyor 38,-a pair of spaced and opposed squeezerolls 31 and 38, a knurling device 39', and the necessary driving mechanism 48 for operating the apparatus; The driving mechanism comprises a motor 45 with a lchainl sprocket 48 mounted on a shaft 41. An endless sprocket chain 48 is mounted on the sprocket and a larger A sprocket 49 mounted on a drive shaft `50. 'I'he drive shaft is' employed to drive the endless conveyor as well as the squeeze rolls. A

Referring V'next to Figs. 8 and 19, sprocket 48 and drive shaft 50l are supported in fixed bearings 5| and v52 suitably mounted on brackets 83' and 54 secured to pedestals 30 and 3|, respectively. A bevel pinion 55 is suitably secured to an intermediate portion of drive shaft 50, the bevel pinion meshing with a bevel gear 58 integrally mounted onthe lower end of a vertical shaft 51. The shaft extends upwardly through a collar 58, a lower xed bearing'block-59 provided with a lower bearing hub 80, and an upper' bearing hub 8|, squeeze roll 38, upper fixed bearing block 82 provided with a lower bearing hub 83 and an upper 4bearing hub 84, anda spur gear 85 integrally securedto the upper end. An end plate 88 is bolted to the ends of Ylower fixed bearing block 59 and upper fixed bearing block 82. Spur gear 85 meshes with a companion spur gear 10 integrally secured to theupper end of a vertical shaft 1|. This shaft extends successively through an antifriction washer 12, an upper laterally sliding bearing block 13, provided with four (4) guide bars 13', as shown, extending through a complementary slot 14 in upper'fixed bearing block 82,'squeezeroll 31,' a lower laterally sliding bearing-block 15, provided withv guide bars as shown, extending through a complementary. slot 18 in lower fixed bearing block 59.

The arrangement shown permits a variable space 80 between squeeze rolls 31 and 38. The apparatus is so designed that the space may be varied to accommodate nuts of various sizes. To this end, upperflxed bearing block 82 is provided at its end with a lateral opening 8| accommodating a draw nut 82. 'The draw nut, as shown in Fig. 19,-is provided with a generallyv rectangular end or base portion 83 and a cylindrical hub por-- 'opening 85, respectively An end plate 89 is secured to the free ends c. lower fixed bearing 88 and upper fixed bearing block 82, as shownr in Fig. 8, by a plurality of bolts. Cylindrical hub portion 84 of draw nut 82 is in turn provided with a lateral square-threaded opening 80 in which ts a complementary square-threaded draw screw 8|,

the other end of which terminates in a shaft extension 92 extending through the bearing 83 of a draw bar 84 secured to upper lateral sliding bearing 85.1nto whichts a complementary squarethreaded draw screw 88, the other end of which terminatesv in a shaft extension 81 extending through the bearing 88 of `a draw bar 89 secured to lower lateral sliding bearing block 15 by means of 9, plurality of bolts.'

As shown in Figs.`8 and 19, end plate 88 is provided `at its end with slots |00 and'i0l to accommodate draw screws 9| and 98, respectively. A squeeze roll adjustment gear` |05 isvintegrally secured to the free end of shaft extension 82, the hub'portion of the gear being in contact with hub 88of draw bar 84 to make a tight assembly. Acoinplementarysqueeze roll adjustment gear |08 is' integrally lsecured to the free end of shafty extension 81, the hub portion of the gear being in`contact with hub 98 of draw bar 88 to make ya tight assembly. Asqueeze roll adjustment -pinion |01 fits in meshed engagement with and between adjustment gears |05 and |08, theipinion beingl integrally secured-to a shaft |88, |the inner end of which fits in a sleeve bearing |08 fitted in and secured to the mid-portion of end plate 88. A pair of spaced flanges I0 and provide a space in which gears |05 and |08 may -turn in meshed engagement with the teeth of pinion |01. The other end of shaft |08 is squaredinto a gripping portion |I2 adapted to fit into a socket crank ||3 (see also Figs. 1 and 27).

Taking up endless conveyor 38, which is shown in Figs. 1, 3, 4, 5,6, 7, 8, and 21, particularly, it will be seen that a conveyor drive sprocket I|8 is secured to power drive`shaft50. .An endless Adrive chain 8 is mounted on sprocket ||5, and av sprocket ||1 integrallymounted on a power take-of! shaft H8'V (see Figs. 1 and 1). The shaft is in turn mounted in a pair of spaced bearings ||8 and |20 attached to a generally horizontal support |2| by a, 'plurality of bolts (see Fig. 7). The endless conveyorv proper comprises lapair of spaced endlesssprccket chains and |28 niountedon a pairof sprockets |21` and |28 respectively, integrally secured tc shaft ||8, and a p'air of spaced sprockets |29 and |30 mounted jon a shaft i3i, the ends of which are supported in a pair of spaced bearings'. |32` and |33 secured te horizontal lsupport |2| with a plurality ofbolts (see Figs. 20 and 21). `A plurality ci? links |35 extend completely around the endless conveyor, the being attached at their sides to sprocketv chains |25 and |28. A sheet metal guard |38 is riveted to each link to provide a cover over the space between adjacent links (see Figs. 3, 4, 5 and 6). Each link is, in addition, provided with a central opening |31 (see Fig. 5) extending through a depending boss |38 under each link. A mandrel support |39 fits in opening |31, the

upper end of which is provided with an enlarged i adapted to fit into the threaded hole of a blank i nut |41, a laterally extending base |48 being provided between the mandrel proper and the depending extension arm which is designed to bear against the top oi. boss |40. This mandrel is also shown in Figs. and 11. Set screw |42 may be turned to secure the depending extension armsecurely.

As shown more particularly in Figs. and 21, longitudinal support I2I is in effect divided into a front portion |50 and a back portion I5I which are joined by a constricted central portion |52 reinforced by a pair of spaced reinforcing members |53 and |54. Front portion |50 has a cut-away portion |55 to accommodate sprockets |29 and |30, and back portion I5| has a cut-away portion |56 to accommodate sprockets |21 and |28. Front portion |50 is provided with a pair of slack-takeup devices |10 and I1.I adapted to move bearing blocks |32 and |33. respectively, in order to take up slack in endless conveyor 36. A pair of spaced mandrel guides |12 and |13 extend lengthwise across -the mid-section of longitudinal support I2I. Guide |12 is fastened to brackets |14 and |15, while guide I 13 is fastened to brackets |16 and |11. A pair of sprocket chain guards |18 and |19 similarly extend across longitudinal support I2I and are secured to the same brackets. l

As shown in Fig. 8, constricted central portion |52 of longitudinal support |2I, in other words the section of the support between front portion |50 and back portion I5I, rests in a recess |80 in lower fixed bearing block 59, the recess being somewhat wider than the constricted central portion to permit lateral sliding movement of the latter. An aligning plate I 8| extends across the top of constricted portion |52 as well as fron-t and back portions |50 and |5| directly below mandrel guides |12 and |13. As more particularly shown in Fig. 8, each mandrel support I 39 is adapted to move along the top of the align-lng plate, thus accurately locating each nut |41 mounted on its mandrel with respect to squeeze rolls 31 and 38. To assist in saddling longitudinal support I2I on lower iixed bearing block 59, front portion |50 of the longitudinal support is provided with a pair of vertically-spaced and laterallyextending -pads |82 and |83 adapted to bear against the side of the bearing block. A similar pair of pads |84 and |85 is provided on back portion I5| of the longitudinal support adapted to bear against the other side of the bearing block. A pair of spaced struts |86 and |81 extend from front part |50 to back part I5! of longitudinal support AIi'l directly below bearing block 59, the struts being provided with a pair of nuts at each threaded end to permit the desired adjustments.

Referring 'more particularly to Figs. 3, 9, 17 and 18, the apparatus shown includes a nutaligner |90 which comprises a pair of spaced and parallel guide wires I'9I and |92 extendingin the direction of the endless conveyor, wire |92 extending forward farther. than wire |9I. The wires are spaced a predetermined distance apart so that when nut |41 mounted on mandrel |46 is passed toward the squeeze rolls and the side of the nut strikes wire |92 and passes :between both wires, the wires function to align opposite sides of the nut in parallel relationship with the .wires so that the opposite sides of the nut are presented simultaneously for engagement with the squeeze rolls. The ends of wire I 9| are secured to a pair of upright supports |93 and |94, in turn secured to brackets |95 and |96, which are fastened to the sides of upper fixed bearing block 62. The

ends of wire |92 are similarly secured to a pair of upright supports |91 and |98. in tum secured to a lateral bracket |99 which is fastened to the inner end of upper laterally slidable bea i block 13.

A draw nut 205 -with a generally rectangular end or base portion 206 and a cylindrical hub portion 201 is secured to front portion |50 of longitudinal support I2I (see Figs. 3, 7, 9, 17, 20 and 21, and -particularly Fig. 17). In similar fashion, a draw nut 2| 0 with a generally rectang-ular end or base portion 2| I and acylindrical huib portion 2 I 2 is secured to back portion I5I of longitudinal support I2I. Hub portions 201 and 2|2 are provided with square threaded lateral openings into which fit complementary square threaded draw screws 2 I3 and 2 I4, respectively. Draw screw 2I3 is mounted in a bearing 2 5 integrally supported by a .bracket 2 8 secured to lower xed bearing :block 59, the draw screw being provided with a pair of collars 2|1 and 2I8 secured thereto at either side of bearing 2 I 5. An endless conveyor adjusting gear 2I9 is mounted at the other end of the draw screw. In similar fashion, draw screw 2|4 is mounted in a. bearing 225 integrally supported by a bracket 225 secured to lower fixed bearing block 59, the draw screw being provided with a -pair of collars 221 and 228 secured thereto at either side of bearing 225. An endless conveyor adjusting gear 229 is mounted at the other end of the draw screw.

Referring to Figs. 8, 9, 17 and 27, it will be seen that shaft extension 92 of draw screw 8| is keyed to and extends through hub 235 of adjusting gear |05 a convenient distance, the shaft extension being provided with an elongated lateral opening 236 in which an indicator shaft 231 is securely fitted. As socket crank II3 is turned to move upper laterally slidable bearing block 13 and lower laterally slidable :bearing Iblock 15, and hence endless conveyor 36, and their related parts, back and forth, indicator shaft 231 also turns. The outer end of indicator shaft 231 extends through a fixed bearing in casing or cove:` 35. An indicator pinion 238 is secured to the indicator shaft intermediate hub 235 and cover 35, the teeth of which mesh with theteeth of an indicator gear 239 mounted on a. second indicator shaft 240 extending through a bearing secured in cover 35, the outer end of shaft 240 being provided with an indicator hand 24|. fashion, the outer end ofv first indicator shaft 231 is provided with an indicator hand 242. Referring next to Fig. 28, it will be seen that indicator hand 242 is associated with an outer calibrated scale 243, advantageously subdivided into thousandths of an inch. As shown, the scale is subdivided into main graduations of ten thousandths of an inch, totalling 250 thousandths; in other words, 1A inch. Indicator hand 24| is associated with an inner calibrated counter scale 244 subdivided as shown into main graduations of 25 units, totalling 150. Movement of larger indicator hand 242 yin a .clockwisedirection from zero all the way around the scale back to zero simultaneously moves smaller indicator hand 24| in a counter-clockwise direction one main graduation, namely 25 units; that is, 1A, inch. A movement of the smaller indicator hand from 0 to O, namely 150 units, corresponds to 11/2 inches. The object of the arrangement described is to indicate to the operator the amount of space existing between squeeze rolls 31 and 38 or the amount of adjustment to be made in the space between therolls. The size of pinion |01, gears In similar I way in space 80 between squeeze rolls |05, |06, 2|9 and 229 and their teeth and the size of draw screws 9|, 96, 2|3 and 2|4 and their threads are so proportioned. and correlated that 'when crank ||3yis turned, squeeze roll 31 moves laterally twice as far as endless conveyor v36. This permits the centering of each nut |41 mid- 31 and 38.

As stated above in referring to Fig. 1, the apparatus includes a'knurling device 39. The object o1' the knurling device is to provide the deformed nuts, that isthe lock nuts, with a suitable marking so that they may be distinguished readily from conventional nuts and to indicate `what portion of the nutis deformed. In the present construction, the knurling device cuts a crisscross pattern of lines inthe top of the lock nuts. The device is shown in more detail in Fig. 3, and

particularly Figs; 22 to 26, inclusive. Power v take-off shaft H6, which operates endless conveyor 36, is also used to operate the knurling device. For this purpose, the far end of the shaft is provided with a gear 250 which in turn meshes with a -geaz` 25| mounted on a horizontal Jack shaft 252 extending back over and across the endless conveyor. The jack shaft is supported in a pair of the former bearing being bolted to a pair of spaced vertical columns 255 and 256 and the latter bearing :being bolted to a sim-liar pair of spaced vertical columns 251 and 258, the bases of the columns being bolted to back portion |5| `of horizontal support |2|. The other end ofthe 'jack shaft is fitted with a sprocket 259 on which is mounted an endless sprocket chain 260, also f mounted on a sprocket 26| on a shaft 282 ex- `tending laterally back over the endless conveyor. Shaft 262 rests in two split bearings 263 and 264, with a knurlerrroll 285 -positioned therebetween,

the bearings extending horizontally between a` pair of vertical columns 266 and 261 near one end and a similar pair of vertical .columns 268v and 269 near the other end, all of the columns being secured at their bottoms to back portion |5| of horizontal support |2| and theirupper ends being threaded, as shown. f

The four upright columns are fitted with three platens, a lower platen 210, a middle platen 21| and an upper platen 212. Theupper platen is provided with a rising central rib section 213 at one end and'a similar rising rib section 214 at the other end. these ribbed sections connecting with a centrally disposed and a wider bearing portion 215. The threaded'end of each vertical column 261, 268 and 269 ts in a threaded sleeve 216 extending through the platen, the sleeve in turn being keyed in each case to a sprocket 211, the construction being identical for the assembly at lthe upper end ofthe three vertical columns. The fourth vertical column 266 is provided with a modified sprocket 218, secured to a special sleeve 219, theupper end of which terminates in an extension portion 280 adapted to fit into a socket crank. An endless sprocket chain 28| is mounted on the four sprockets.

A vertical shaft 285 extends through bearing portion 215 of upper platen 212, the lower end terminating in a head 288 to help hold it in position, the upper portion of the shaft having keyed thereon a pinion 281 meshing laterally with a pair of gears 288 and 289. The upper end of shaft 285 spaced bearings 253 and 254, v

terminates in an extension portion 290 adapted being adapted toengag'e lo; I l a central rib 292 of middle platen 21|. Gear 299 carries a similar thrust screw l293 to bear uponthe rib 292. An upper boss 291 and a lower boss 298 are provided at each of the holes in lower platen' 210 through which the vertical columns extend, to provide more be'aring and guiding surface. Split bearings 263 and 264 are integrally secured to the bottom of lower platen 210 by means of a plurality of stud bolts 299. The lower platen has a cut-away portion 300 through which the upper portion of knurler roll 265 extends. Reinforcing plates 30| are secured at opposite sides to strengthen the platen in the areas adjacent cut-away portion 300.1 v

A plurality of appropriately spaced bolts 305 extend through upper platen 212, middle platen 21| and lower platen .210 and split bearings 263 and 264 to help support the lower portions of the split bearings.A In addition, each bolt is provided with a compression spring 306 between middle platen 21| and lower platen 210. As a result'of the arrangement described, shaft 262 and'therfore knurling roll 265 are held in a position to be moved upwardly or downwardly, as desired.'

A rough approximation for the operative v'posi'- tion of the knurling roll is advantageously first obtained by fitting a socket crank on extension portion 280 and turning it to move sprocket chain 28| around sprockets 211 and 218 and hence to move upper platen 212 up or down, as required. This is done to place thrust screws 29| and 293 in a favorable operative position. When, therefore, a socket crank is tted onto extensionportion 290 of vertical shaft 285, thrust'v screws I29| and 293 are moved upwardly or downwardly, depending upon the direction of rotation of the socket crank. If thrust screws 29|' and 293 are forced downwardly against centralv rib 292 of middle platen 21|, springs 306 are placed under greater compression, thus forcing lower platen 210 and hence shaft 262 and knurler roll285 downwardly. In other words, the knurlerA roll is forced more heavily against the top'of deformed nut |41, and succeeding deformed nuts |41. If, however, the pressure of the knurler roll ori the nut is-too much, the operation may be reversed to release the .compressive force of springs 306. Minute control of the amount of pressure of the knurling roll on the nut may thus be obtained by the use of the socket crank on extension portion 290.

The apparatus shown includes special means for withdrawing the deformed-nuts from the mandrels as the endless conveyor moves around to its discharge end (see Figs. 1, 'l and 22). For this purpose, the apparatus includes a pair of spaced supports 3|0 and 3H, the upper ends of which are attached to upright columns 251 and 255, and

vthe lowerl ends to back portion |5| of horizontal support |2 A pair of spaced deformed nut strippers 3|2 and 3|3 are suitably suspended from supports 3|0 and 3H by a plurality of lateral arms 3|4. These strippers consist of strips of thin curved sheet metal, the inner edge portions, of which are adapted to engage the bottoms of the deformed nuts. As'shown in Fig. 1, the curvature of the strippers is such as to follow each mandrel to its upper end as it moves around the discharge end of the endless conveyor; that is, around chain sprockets |21 and |28. Therefore, as the fore or top parts of the strippers engagev the lbottom of each nut in its normal position on the mandrel, and the mandrel continues in its cour'sejaround the sprockets, the deformed 'nuts ride on the strippers and are gradually moved upwardly tc 1l the top or `end of the mandrels, from which the nuts are dropped. A chute 3I5 islocated at the discharge end of the endless conveyor, being secured to cover 35, as shown in Fig.11, to catch the nuts and direct them into a bin 3|6 located under the chute.

In referring to Figs. v5,10 and `11 above, brief reference. is made` to mandrel |46. As more clearly shown iny Figs. and 11, ythe mandrel proper is divided into a lowerV cylindrical base portion 325, adapted to fit loosely in the lower portion of blank nut,|41, and an upper cylindrical stop` portion 326 of predetermined size adapted to act as a stop (see Fig. 11) when squeeze rolls` 31 and 38 force opposite sides of the upper portion of the nut toward one another and the upperl threads .of the nut are brought into engagementwith the stop portion. A modied form of mandrel |46 is illustrated in Fig. 12, in which base portion 325 and stop portion 326' are in thevshape of a frustrum kof a cone. In both constructions, vthe surfaces are relatively smooth. The presently preferred construction is that of Figs. 10 and 11 because the cylindrical base and stop portions may be readily machined to size.

Lock nut |41 is shown in hexagonal form withV a threaded central opening 33|. The opening at the bottom portion 332 of the blank is circular but at the upper portion 333 it is generally elliptical, having a minor axis 334 and a major axis 335. The elliptical shape of the opening at the upper portion of the blank is the result oi compressing or squeezing the upper portions 336 and 331 of opposite sides of the main body of the blank toward one another at the top portion to a depth of 1A to 1/2 the nominal diameter of the mating screw beyond the elastic limit of the blank to provide a permanent distortion in the blank with the sides 338 and 339 of the opening on minor axis 334 pushed toward one another and with the sides 340 and 34| of major axis 335 pushed away from one another. The width of the top of the opening along the minor axis is reduced by the distortion by an amount equal tothe flt tolerance plus 0.001 to 0.010 inch. The amount of inward distortion may be determined by measuring the distance from crest to crest of the first or upper full thread in the opening. This may be done with a Vernier caliper or a taper plug gauge.

In a presently preferred practice of the invencordingly,

12 axis 334 o! the nut tightly` engage their mating threads on the bolt. This spring action causes the nut to grip opposite sides of the bolt and by reason of the amount of the distortion to make a strongl'i'riction pressure contact on the top as well as on the bottom of the bolt threads. Ac-

the nut notonly grips the bolt tightly but creates an additional friction area on the threads by pressing against the upper as well as the llower sides of the bolt threads even when the nut is tightened against the Work. l

Inorder that lock nuts made according to the invention be of general utility, it is highly desirable that they be adapted to receive standard socket wrenches and box end wrenches, as well as open end wrenches. In distorting the nut, its outside dimension measured at right angles to the direction in which it is squeezedis increased slightly. In other words, the distance across the nut is decreased along minor axis 334 and increased along'major axis 335. This increased outside dimension along the major axis may be too great vto permit placing a standard socket wrench or box end wrench of nominal size over the nut. It is therefore desirable to make the nut blanks in, for example, hexagonal form, somewhat smaller in cross-section than the conventional y practice so that when the distance across the top ofthe lock nut is increased along its major axis, the nut may nevertheless fit into the wrench. i

Some important advantages of the lock nut of the invention are its ease of manufacture; its ease of application; it may be tightened without damaging its own or its mating threads; it may be removed from a bolt without excessive dimculty; and it may be used again and again on the same bolt or on a different bolt. In addition, the lock nut locks itself to a bolt by a clamping action strong enough to resist loosening under severe vibration or repeated heavy shocks.

'I'he application just described may be operated as follows:

Crank 3 is turned clockwise or counterclockwise, as required, to adjust the width of space 80 between squeeze rolls 31 and 38 to accommodate the particular size of nut blank |41 to be deformed. In Fig. 17, for example, the nut is relatively small while in Fig. 9 it is relatively large. Operation of crank ||3 simultaneously adjusts the space between parallel guide wires tion, the width of the top of the opening along,

the minor axis is reduced by the distortion by an amount to produce a friction locking torque of 115D2-4 to 820D2-5 on a mating screw within the dimensional tolerances of its class of t, in which D equals the nominal diameter of the mating screw and the result obtained is -pound' inches of torque. 1 This value may be readily determined by serewing'the lock nut on a mating-screw, such as a bolt, with a conventional torque wrench.

Fig. 16 illustrates the use of the lock nut when screwed tightly onto a bolt 342 to secure the pieces of work 3113v and 34111.V When the nut is applied to the bolt, it may be screwed at least A of the way freely by hand'since thelower part of the nut is not distorted. As the nut is vscrewed further onto the bolt,- the distorted upper portion of the nut tends toassume its original undistorted'f'orm due to the resiliency of the metal wall ofthe nut. `The boltthreads force the compressed sides of the nut apart against'the spring action of the distorted upper portion of the nut. As,indicated in the drawing, the threads along the-inwardly distorted sides 338 and 339 on minor |9| and |92. Motor 41 is started which in turn sets squeeze rolls 31 and 38, endless conveyor 3B and knurling device 39 in motion. The driving parts are so proportioned and correlated that the endless conveyor, squeeze rolls and knurler move at` substantially the same linear speed. A nut blank |41 is mounted on the free end of each mandrel |46 as it approaches the parallel guide wires and the squeeze rolls. If a corner or corner position of the nut strikes guide Wire |92, the nut is turned on the mandrel to align a pair of its opposite sides in parallel relationship with the guide wires. This relationship is maintained as the nut moves forward into additional sliding contact with guide wire |9|. This operation assures proper presentation of the nut rto the squeeze rolls.

The squeeze rolls and the nut on the mandrel are so positioned that only the upper portion of the nut comes into squeezing engagement with the rolls, the depth of squeeze, as pointed out above, being 1A to 1/2 the nominal diameter of the mating screw. Since both squeeze rolls are power driven, the upper portion of the nut is readilygripped by the ,rolls and deformed asit passes between them. The thrust of the rolls is vdirectlytoward one another so that little or no resultant force extends downwardly toward laterally extending base |48 of the mandrel.

Crank I |3is suitably turned to provide space 80 between the squeeze rolls with the, necessary width to deformthe upper portion of the nut the requisite amount; upper portion 326 of the mandrei acting vas a stop against excessive deformation vwhile at the same time assuring each suc- Iceeding nut of an equivalent amount of deformation, falling within the limits above mentioned. In practice, nuts as they come from the-squeeze rolls are'fmeasured to determine whether the width of the top of the opening along the minor axis is reduced -by the distortion by an amount equal to the iit tolerance plus 0.001 to 0.010 inch. 'I'hey are preferably tested with a torque wrench to determine whether the width of the top of the and the result obtained is pound inches of torque.

An intermediate optimum value is selected and crank la is turned this way or that until the distorted nuts coming from the squeeze rolls match that value. Such checks and adjustments, if necessary, are made from time to time. during the course of a days operation of the apparatus to make certain that the lock nuts produced are substantiallyv uniform in theirv friction locking torque.

Although provision is made for knurling the top of each lock nut as it leaves the squeeze rolls, this is a convenience rather than a necessity. Furthermore, the nut blank could be knurled before it enters the squeeze rolls, or for that matter, before it is mounted on its mandrel. Among important advantages ofthe practice disclosed are the following: 'I'he knurled top at onc'e identiiles the nut as a lock nut. Second, it indicates to the user that the knurling is adjacent the upper or distorted portion of the nut and that the unknurled bottom should be presented to a mating bolt to assure easy screwing of the nut at least until the rst threads of the bolt come'into intertering or locking engagement'with the distorted threads of the lock nut. In addition, a distinctive knurling design may be employed to identify the manufacturers particular brand of lock nut. In any event, as a given mandrel and nut are carried as a unitby the conveyor between the squeeze rolls, they pass under and in contact with knurling roll 265. As pointed lout, above in suillcient detail, various parts of the knurling device may be manipulated to vary the pressure ofthe roll on the top of 'the nut to assure the desired marking. l

The conveyor then carries each succeeding knurled lock nut while still mounted on its mandrel to strippers 3|2 and M3 where the nuts are forcibly removed, dropped rst into chute 3| 5 and then into bin 3 I 6.

It will be clear to those skilled in this art that the specific method and apparatus lust described may be suitably varied while still falling within the purview of the invention.

14 bination of mechanisms other than vthe device i'or knurling the top of the nut while it is, on the mandrel; `whilein my application Serial No. 621,273,11 have claimed amethod by which the nut is compressed at the sides and knurled at the top, which method may be practiced expeditiously rolls forforcing opposite sides of the nut toward yone another until threads im the hole of the nut vengage the stop portion of the mandrel to distort the nut' a predetermined amount, one of the squeeze rolls being connected with means to cause its rotation in a clockwise direction and the other squeeze roll being connected with means to cause its rotation in a. counter-clockwise direction, means for moving the endless conveyor and hence each mandrel with a nut mounted thereon toward and between the squeeze rolls at substantially the same linear speed as that of the squeeze rolls,

and a knurling device located adjacent the path of the conveyor in spaced relation to the squeeze In my co-pending applications Serial Nos. 621,-

rolls for knurling the top of the nut.

2. Apparatus according to the preceding claim,

in which the knurling device is provided with a knurling roll in spaced relationship to the con- A veyor so that when a nut mounted on its mandrel passes by the knurling roll the top of the nut is knurled..

. 3. Apparatus according to claim 1, in which the knurling device is provided with a knurling roll in spaced relationship to the conveyor directly beyond the discharge side of the squeeze rolls so that when a nut mounted on its mandrel is passed from the squeeze rolls to the knurling roll the top of thenut is knurled,'and means for rotating the knurling roll at substantially the same linear speed as that of the conveyorand squeeze rolls.

4. In apparatus for manufacturing lock nuts, the improvement comprising a mandrel adapted to be inserted in the threaded hole of a nut blank, the mandrel being provided with a stop portion of predetermined size, a pair of opposed and spaced squeeze rolls for forcing opposite sides of the nut toward one another until threads in the hole of the nut engage the stop portion of the mandrel to distort the nut a predetermined amount, a knurling device coacting with the mandrel and squeeze rolls for Vknurling the top of the nut, the knurling device including a knurl ing roll adjacent the free end o f the mandrel.

and means for turning the squeeze rolls andthe amount, a conveyor supporting the mandrel for passing the mandrel and a nut mounted thereon as a unit between the squeeze rolls, and a knurlmg device spaced from the squeeze' rolls and lo- 4 cated adjacent the l5 f path of the conveyor for knurling the top of the nut, the knurling device having a knurling roll adjacent Vthe tree end of the mandrel, and means for moving the conveyor. the squeeze rolls and the knurling roll at substantially the same linear speed.

6. Apparatus according to claim 5, in which the knurling device is positioned directly beyond the discharge. side of the squeeze rolls.

7. In apparatus for manufacturing lock nuts, the improvement comprising a mandrel adapted to be inserted in the threaded hole of a nut blank, the mandrel being provided with a stop portion of predetermined size, a pair of opposed and spaced squeeze rolls for forcing opposite sides oi.' theA nut toward one another until threads in the hole of the nut engage the stop portion of the mandrel to distort the nut a predetermined amount, a conveyor supporting the mandrel for passingthe mandrel and a nut mounted thereon as a unit between the squeeze rolls, and a knurling device spaced from the squeeze rolls and located adjacent the path of the conveyor in position to and the conveyor.

erliageandknurithetopofanutontheman- JOHN w. Nm.

REFERENCES CITED .The following references are of record in the tile of this patent:

UNITED STATES PATENTS Name Number Date Sharp July 9, 1935 

